Moina macrocopa is a toxicologically less explored, yet widely distributed freshwater cladoceran found throughout the world. The present study is aimed at determining the cadmium (Cd) bioaccumulation and Cd-induced molecular and biochemical biomarkers, including DNA damage and antioxidant enzyme responses (i.e., catalase (CAT) and glutathione S-transferase (GST) activities), in M. macrocopa neonates. Cd bioaccumulation was determined using a Cd-sensitive fluorescence probe after acute exposure to Cd. The results indicated a concentration-dependent Cd bioaccumulation, especially in the gut region, where it was statistically significant in neonates exposed to ≥5 Cd μg/L. DNA damage was determined by the randomly amplified polymorphic DNA (RAPD) technique after a short-term exposure to sublethal Cd concentrations. Significant DNA alterations were observed in individuals exposed to ≥10 Cd μg/L. Short-term exposure to sublethal Cd concentrations did not change CAT levels. However, low Cd concentrations (10 μg/L) significantly induced GST levels, and higher concentrations (50 μg/L) significantly inhibited the GST levels. Taken together, the results of the present study indicated that bioaccumulation of Cd in M. macrocopa causes oxidative stress even at sublethal concentrations, which may be one of the underlying causes of the observed DNA damage. Furthermore, the findings of the present study highlight the importance of utilizing molecular and biochemical biomarkers for toxicity assessment in cladocerans owing to their high sensitivity and rapid responses even under short-term exposure conditions with low concentrations.